Electric-lamp socket



May 13', 1924. v v/)fgss RKB. BENJAMIN ELECTRIC LAMP SOCKET Filed Sept.27 1919 2 Sheets-Sheet 1 v v /NI/EN TOR.

' TToR/VEY May 13 1924.

R. B. BENJAMIN ELECTRIC LAMP SOCKET Filed SeD'.. 27

ASSSQS 2 Sheets-Sheet 2 w IN1/E /TOR mM/27172 WR A/ TOM/EY Patented May13, 1924.

PATENT OFFICE.

REUBEN B. BENJAMIN, OF CHICAGO; ILLINOIS, ASSIGNOR TO BENJAMIN ELECTRICMANUFACTURING COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

ELECTRIC-LAMP SOCKET.

Application filed September 27, 1919.

T 0 all whom t may concern.' p

Be it known that I, REUBEN'IB. BENJA- MIN, a citizen of the UnitedStates, residing at Chicago, in the county of Cook and State ofIllinois, have invented new and useful Improvements in Electric-LampSockets, of which the following is a full, clear, concise, and exactdescription, reference being had to the accompanying drawing, forming apart of this specification.

This invention relates to an electric lamp socket, and moreparticularly7 to an electric lamp socket construction in which theswitching member is provided with improved means for introducing adouble break in the circuit continuity. The general trend of lamp socketconstruction, in view of the present day universal use of electricalhousehold appliances of high wattage consumption, is directed to socketsof increased power rating. This increased wattage rating for lampsockets may be obtained in a variety of ways, one of which consists inincreasing the number of breaks introduced into the circuit by theswitching mechanism.

It is one of the objects of this invention to produce a lamp socketiitted with an ims proved mechanism for obtaining a plurality of breaksin the circuit continuity in the operation of the switch mechanism.

Another object of this invention consists in the production of animproved switch mechanism in which arcing at the switch contacts, due tothe opening of the circuit, is maintained at a minimum.

Another object consists in the production of an improved switchmechanism of this character which is simple in construction, reliable inoperation, and which is very compact, whereby it can bereadily andefliciently assembled in lamp socket construction.

Other features, advantages, and objects of this invention will becomeapparent from the accompanying illustrations, the following description,and the appended claims.

For the purpose of describing and illustrating the invention, a specificembodiment thereof is illustrated in the accompanying drawings in whichFig. 1 is a plan view of the lamp socket construction with the cap ofthe socket removed to disclose the switching mechanism;

Fig. 2 is a View of the socket construc- Serial No. 326,831.

tion taken on the plane represented by tne line 2 2 of Fig. 3 looking inthe direction of the arrows;

Fig. 3 is a vertical section of the socket construction taken on a planerepresented by the line 3 3 of Fig. 1 looking in the direction of thearrows;

Fig. 4 is a vertical section of the upper portion of the socket taken onthe plane represented by the line 4 4 of Fig. 1 looking in the directionof the arrows, and illustrates the switching mechanism in the closedposition;

Fig. 5 is an illustration similar to Fig. fl, showing the switchingmechanism operated to the open position;

Fig. 6 is a vertical section of the upper portion of the socketconstruction taken on a plane represented by the line 6 6 of the Fig. 1looking in the direction of the arrows;

Fig. 7 is a Vertical sectional View taken on the plane represented bythe line 7 1 of Fig. 1, and illustrates the method utilized foranchoring the pawl operating spring in the insulating base;

Fig. 8 is a perspective view of the commutator, consisting of acombination ratchet and cam wheel;

Fig. 9 is another view of the commutator, and illustrates the reverseface to that shown in Fig. 8;

Fig. 10 is a view in perspective of the pawl plate utilized to rotatethe ratchet, and

Fig. 11 is a View similar tor Fig. 5, but showing the switch with theparts 1n tne positions which they occupy just as the first break in thecircuit occurs.

As illustrated in the drawings, the socket mechanism is preferablyenclosed in a metallic casing consisting of the lower shell 16 and thecap 17. The lower shell 16 is fitted with a downwardly extendingcylindrical portion 18 off-set from the upper portion thereof by anannular ledge 19 and fitted within the portion 18 is a circular insulating member 2O which separates the portion 18 from the threaded shellcontact of the socket 21. The cap 17 is connected to the lower shell 16in any suitable manner, a large number of which are well known to thoseskilled in the art, whereby a positive lock is obtained between theshell 16 and the cap 17.

In the specific embodiment of the metallic shell 16 a lateral outlet 22is provided for attaching the socket mechanism to a fixture. Thisfixture attaching portion 22 makes the specic embodiment of theinvention, herein illustrated, an angle socket, but obviously theinvention can be readily incorporated in any or all of the various typesof lamp sockets known to the art.

On the down turned upper portion of the insulating sleeve 20, whichrests on the annular ledge 19, is an insulating base 24 which serves toreceive and mount the electrical switch mechanism, as well as the lampsockets and circuit terminals.

The switch operating mechanism is located in a chamber 25 in the base24. The switch mechanism includes a commutator comprisingl` a cam Wheelhaving two cams; one of which has a greater lift than the other, thesecams operating upon a turn of 180 degrees and the face of one cam beingof conducting material while the face of the other is of insulating`material. Combined with this cam wheel, and preferably formed integraltherewith, is a ratchet disc, the periphery of which extends beyond thesurfaces of the cams and forms a barrier between the live parts of theswitch and the operating means. The ratchet disc portion of thiscommutator is formed with ratchet teeth preferably made by indenting orforming notches in the side of the commutator opposite the cam wheelportion thereof. To advance the commutator through 180 degrees ofrotation upon each operation of the mechanism, there is provided aratchet plate which is formed with ratchet pawls or teeth to engage theratchet notches of the commutator, and is also provided with a chainrail to carry and guide a chain and also with a forked portion adaptedto receive the end ball ofthe operating chain. Suitable spring means areprovided for returning the ratchet plate and chain after each operationof the switch so that the parts are ready for the next manual operationof pulling upon the chain and advancing the commutator through another180 degrees of rotation. Combined with this commutator is a novel formof circuit breaking device which opens the circuit at two points inseries, upon alternate pulls upon the chain. ln the chamber 25 of thebase 24 is positioned a spindle 26 which is rotatably mounted in a slot2.7 cut in one of the walls of the chamber of the insulating base 24(see Fig. 7), the other end of the spindle being rigidly secured to thecommutator 28, which consists of a coinbination ratchet and cam wheel,as above stated.

The ratchet and cam wheel 2S is composed of some suitable insulatingmaterial, and comprises the enlarged disc portion 29, preferablyintegral with which is the double cam wheel 30. The maximum radius ofthe cams being less than that of the disc 29, said disc constitutes aperipheral flange extending beyond the periphery of said cams. rl`hisflange acts as an insulating barrier between the conducting andoperating parts of the switch mechanism which will become apparent fromthe following description and will be evident from Figs. l and 3. Thecam wheel portion of the commutator has two cam faces 3l and 32, eachsubstantially 180 degrees in length. The cam face 8l has a very slightand gradual rise, while the cam face 32 has a larger rise or lift. Fromthe cam faces 3l and 52 there is an abrupt or sudden drop, as shown at33 and respectively. rEhe drop is much greaterl from the face 3l thanfrom the other face. rlhe spindle 26 is preferably secured to thecommutator 28 by embedding the end thereof in the insulating material ofwhich the latter is constructed. rlhe cam face 3l consists of a contactplate 35 which is provided with an arm 36 extending over the side faceof the cam wheel to the central portion thereof, where said arm isformed into a hollow metallic sleeve 87, which fits over the projectingcylindrical hub 38 of the commutator 28. Said hub 3S and the enclosingmetallic sleeve 37 constitute a journal for the commutator and alsoserve as the other support for the spindle 2G. The metallic journal 38is supported in a plate or bearing bracket 40, which is of conductingmaterial. The conducting bracket 4() is secured to the base 24 by meansof a screw 4l, the head-end of which is connected by means of aconducting plate 42 to the center contact 43 of the lamp socket.

From the foregoing description, it will now be apparent that theinsulating commutator is contained in the chamber and is rotatablymounted by the spindle 2G between the slot 27 cut in the insulatingblock r9-land the aperture provided in the conducting plate 40, whichserves as a lx-aring for the metallic sleeve 37.

The chamber 25 has a narrow extension 47 connected to one side thereofin which is mounted the resilient tl-shaped spring 48, which is normallybiased by means of a spiral spring 49 in the direction of thecombination ratchet and fam wheel. The U- shaped spring 48 has one ofits members 49, due to the aforesaid bias, continually in contact witheither one or the other of the faces 3l and 32 of the combined ratchetand cam wheel 28. Consequently, the spring f8-depending upon theposition of the cam wheel-is either in contact with the conducting face35, as shown in Fig. 4, or in contact with the insulating cam face 32,as illustrated in The comn'iutator is operated by means of pawls whichmay be actuated in any desired manne-r. ln the specic embodimentillustrated, the pawls are carried on a metallic ing pawls 56 and 57,which pawls in the assembly of the switch mechanism are placed adjacentthe face 58 of the combination ratchet and cam wheel 28. The discportion 54; is also fitte-d with the outwardly projecting prongs 59 and50, which project from the opposite face of the disc from which thepawls 56 and 57 extend. Sub-A stantially normal to the face of the disc5ft is the flange 54 which lia-nge carries a substantially perpendicularchain rail The chain 53 is attached to the ratchet plate 51 by means ofthe bifurcated arm 52, see Fig. 6, the chain passing over the iange 5l.he. ratchet plate is preferably made from one piece of material punchedand formed into the construction illustrated in Fig. 10.

Either one of the prongs 59 or 60 can be utilized, as illustrated inFig. 6, to se-v cure one end of a spiral spring 61 to the member 51, thespring 61 being sleeved upon vthe spindle 26 and having the opposite end62 thereof secured to a ledge 63 provided for this purpose in theinsulating base 24, as illustrated in Fig. 7. Con sequently when thechain 53 is operated it will carry with it the ratchet plate 51, whichin turn will tension the spiral spring 61. The movement of the' member51 is conn trolled by a projection 64 thrown into the path` of the saidmember. The forward movement of said member under the action ofthevchain 53 will be limited by the engagement of the forward edge 65 ofsaid member with the protrusion 64, and the return movement-'of the saidmember will be limited by the engagement of the bifurcated arm 52 withthe said protrusion.

The face 58 of the combination ratchet. and cam wheel 28 is providedwith the two tapered notches 66 and 67, which notches form ratchetteeth, which cooperate with the pawls 56 and 57 to turn the combinationratchet and cam wheel 28. Thev spring 61A not only returns the pawlcarrying plate 51 to position so that the pawls may engage the teeth 66and 67 but also exerts an expansive force, whereby the disc 51 is heldsnugly in position against the face 58 of the combination ratchet andcam Wheel 28, and the bearing extension 36 of the contact 35 is held ingooi electrical contact with the bearing bracket 40.

Due to this assembly of parts, it will be evident that when the chain ispulled the disc 51 will rotate and will carry with it the combinationratchet and cam wheel 28 until the forward edge 65 of the member 51strikes the protrusion 64;. This marks the limit of the forward movementof the mem: ber 51, and upon the release of the chain 53 the combinationratchet and cam wheel 28 will remainin the position to which it has beenrotated,l as hereinafter to be described; whereas, the pawl carryingdisc 51 will be rotated in the reverse direction under the influence ofthe spring 61 until thebifurcated ends 52 strike the protrusion 64s. Thepawls will then have passed the opposite notches (6G and 67) in the face58 of the combination ratchet and cam wheel 28, and Will engage thereinon the next forward movement of the pawl-carry`A face 35 or theinsulated cam surface 32r of the commutator 2S, the rotation of thiscommutator 28 will obviously cause a movement ofthe U-shaped spring 48.l/Vhen the switch n'iechanisin is in the olf position, as illustrated inFig. 5, the rotation of the commutator will cause the end of the arm 49of the tl-shaped spring 4S to move up on the cani surface 32, andthereby move said lll-shaped spring in a direction away from said camand toward the contacting terminal 70. .ihe movement of this Uishapedspring will take place against the force exerted bythe biasing spring4-9, and therise in the cam surface 32 is such that the arm 71of theU-shaped spring` will move into contact with the contactmember and theU-shaped spring will be considerably compressed before ther high pointon the cam surface 32 is reached. Trnen the high point on the cam sur`ece is reached, the end of the arm i9 of the Ll-- shaped spring 48 willslide over the abrupt stop or shoulder Sli onto the contact plate 35.Thereafter, whenthe pulling force on the chain 53 is discontinued, themember 51 will return to its normal position under the action of thespring 61 as hereinbefore described. The combination cam and ratchetwheel 28, however, vwill remain in its advanced position, being held inthis position by the end of the spring' arm i9 which rests against thestop or shoulder 34. l/Vhen this movement has been completed theswitching mechanism will be in a position shown in Fig. al.

Upon the next operation of the switching mechanism by the pulling of thechain 53, which results in movements in the pawl carrying disc 51 andthe combined ratchet and cam wheel, as hereinbefore described, the armi9 will ride over the Contact surface 35. When the end of the contactsurface is reached, there is an abrupt drop at 33,

whereby contact between the member 49 of the U-shaped spring 48 and thecontact surface 35 is first broken or interrupted, and thereafter underthe action of the resiliency of the U-shaped spring 48 and the biasingaction of the spiral spring 49', the U-shaped member 48 will take theposition illustrated in Fig. 5, thereby interrupting or breaking thecontact between the member 71 of the U-shaped spring 48 and the contactmember 70.

It will now beevident that the cooperative action of the commutator 28and the U- shaped spring 48, is such, that when the switch mechanism ismoved from its open position as illustrated in Fig. 5 to the closedposition as illust-rated in Fig. 4, the U- shaped spring 48 will beforced to the right, so that the arm 71 thereof will contact with thecontacting member 70. In this movement the cam surface 32 will graduallycompress the two arms 49 and 71 of the U-shaped spring 48, and said armswill be under considerable compression when the high point of the camsurface 3Q is reached, whereby good and positive contact will beobtained and maintained between the arm 49 of the U-shaped spring andthe contact member 70.

1When the arm 49 of the U-shaped spring reaches the high point of thecam surface 3Q, and passes over the stop or tooth 34, there will be aresulting slight expansion between the arms 71 and 49 of the U-shapedspring, due to the slight drop at 34, but this expansion is so slightthat good contact will still be maintained between the arm 71 of theU-shaped spring and the contacting member 70, the arms 71 and 49 of theU- shaped spring still being in compression when in this position, asclearly illustrated in Fig. 4. Due to the expansive force of theU-shaped spring 48, therefore, good positive contact is establishedbetween the respective arms of said spring and the contact member 70 andthe rotatable contact member 35.

However, when the switch mechanism is operated from the closed positionshown in Figure 4, to the open position shown in Fig. the arm 49 of theU-shaped spring will ride over the contact 35 until it reaches theabrupt shoulder or drop 33. As clearly illustrated in the drawing thisdrop or shoulder 33 is a comparatively long one, the shoulder drop ortooth 33 being preferably made three or four times as deep as theshallow tooth or shoulder 34. Consequently, when the arm 49 reaches theend of the Contact 35, the drop at the shoulder or tooth is such as topermit the U-shaped spring 48 to expand freely due to its own resilienceand due to the force exerted by the spiral spring 49, whereby due to thedrop, contact between the arm 49 and the contacting surface 33 isbroken, as seen'in Fig. 11, and l immediately thereafter the contactbetween the arm 71 of the U-shaped spring and the contact member 70 isbroken, as seen in Fig. 5 and shown in dotted lines in Fig. 11.

As clearly illustrated in the drawing, the combination ratchet and camwheel member 28 is positioned with its rotation axis transverse to theaxis of the socket and to the direction of pull of chain. Consequently'the chain 53 may be so positioned, as illustrated in Fig. 6, that thepulling force exerted thereon is communicated to the combination ratchetand cam wheel 28 in a direct line without the necessity of looping thechains through any curves or angles, which is ordinarily necessary whenthe axis of rotation of the revolving commutator is parallel to the axisof the socket. Therefore with this construction a direct tangential pullis obtained. Further, since the combination ratchet and cam wheel 28 isprovided with but two cam surfaces and two teeth or shoulders, acomparatively small disc can be utilized, and a good, long, smoothpositive pull will nevertheless be obtained on the chain for theoperation of the switch mechanism. The use of a small disc 28 ispractically imperative for the construction of a satisfactory commercialdevice in order that the desired compactness will be obtained. Becauseof` the use of two cam faces or surfaces, each substantially 180 degreesin length, a long smooth pull on the chain is obtained, notwithstandingthe use of a commutator of small diameter which obviously results in apositive and smooth action of the switch mechanism.

The contact member 70 is integral with the plate 72 which carries thecircuit terminal 73. The other circuit terminal is shown at 74, which isconnected to a plate 75, the plate 7 5 being secured to the insulatingbase by a screw 7G which connects the plate 75 and the circuit terminal74 to the threaded shell contact 21 of the lamp socket.

The circuit of the lamp socket may now be traced as follows:

Assuming that the switch mechanism is in its closed position, thecircuit is traceable from the circuit binding terminal 73 through theplate 7 2 to the stationary contact 70 and thence through the U-shapedspring 48 and the rotating contact 35 by way of the conducting strip 36to the metallic sleeve 37, which is in contact with the conducting barfrom where the circuit is traceable by means of the screw 41 to theconducting strip 42 and the center contact 43 of the lamp socket. With alamp in position the circuit can be traced through the lamp to thethreaded shell contact 21 and thence by means of screw 76 to theconducting bar 75 and the other circuit binding terminals 74.

It will be evident that when the commulnacaesoa tator 28 is rotated, asherenbefore described,

4from the closed to the opened circuit position, that the circuit justtraced will be opened at two points. First, or primarily, at the pointof contact between the member 49 of the U-shaped spring 48 and therotating Contact 35, and secondarily, and inimediately after the primarybreak, at the point of contact between the member 71 of the U-shapedspring 48 and the contact member directly connected to the terminal 73.Likewise, when the circuit is closed, due to the rotation of thecommutator, contact will first be made between the member 7l of theresilient U- shaped spring 48 and the contact member 70, and thereafterwhen the member 49 of the U-shaped spring drops down from the high pointof the cam 32 at tooth 34, the second contact is made between the saidarm 49 and the contact 35. Consequently when the circuit is opened-dueto the operation of the switching mechanism-the circuit will be brokenpractically simultaneously at two points, thereby` very materiallyreducing the resulting sparking at the points of contact andconsequently increasing materially the current carrying capacity of theswitching mechanism.

It will be evident also from the foregoing description that socketsconstructed in accordance with the teachings of this invention are madeof a very few simply constructed parts which can be very compactlyassembled in the limited space available in a lamp socket, and due tothe simplicity of the construction of these parts the operation of theswitch mechanism is exceedingly efficient and reliable.

Obviously, the invention is not limitedv to the specific embodimentthereof herein illustrated and described but is capable of manyvariations and other applications within the spirit and scope of theinvention as set forth in the following claims.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent is:

l. In a device of the character described, in combination, anlinsulating base having a chamber, a combination ratchet and cam wheelconstructed of insulating material, rotatably mounted'in said chamber,lamp contacts and circuit terminals mounted on said base, a conductingplate positioned on the cam wheel and extending substantially over -180degrees of its surface, said combination means being seriallyinterconnected between one of said terminals and one of said lampcontacts, andr means for operating said cam wheel, said wheel having twocams of unequal drop, whereby said conducting member, said contactplate, and said resilient nieans cooperate to alternately open and closethe continuity of the lamp switch circuitr at two points.

2. In a device of the character described, in combination, an insulatingbase having a chamber, an insulating cam wheel rotatably mounted in saidchamberl` a conducting plate on said cam wheel, a journal for said camwheel, said journal being electrically connected to said conductingplate, circuit terminals and lamp contacts carried by said base, a rigidstationary contact member, a resilient means arranged to make and breakcontact with both said'stationary and said rotatable contact, saidstationary and rotatable contacts, together with sa-id resilient means,being serially interconnected -between one of said circuit terminals andone of said lamp contacts, and means for rotating said cam wheel, saidcam wheel being provided with cam portions of unequal drop to cause theresilient means to successively make and break contact with both saidstationary and rotatable contact members. A

3. In a device of the character described, aninsulating base, astationary switch -contact carried by said base, a cam wheel rotatablymounted on said base, a contact member carried by said cam wheel, saidcam wheel having an abrupt drop at the end of said contact member and agradual rise from said drop to the opposite end of said contact memberand a lesser drop to said contact member, a resilient conducting vmemberinterposed between said stationary switch contact and said cam wheel forbridging across from the said stationary Contact to the contact memberon the cam wheel, the drop from the end of said contact member beingsuliiciently great so that said conducting member cannot engage bothsaid stationary contact and said contact wheel at the same time, andmeans ytending to move said conducting member bodily away from saidstationary contact.

4. In a device of the character described, the combination of a base, astationary switch contact carried by said base, a commutator rotatablymounted on said base, said commutator having a non-conducting camterminating in a drop, said commutator having also a conducting camterminating in a drop greater than that of the non-conducting cam, aresilient conducting memi i stationary contact, the drop at thetermination of said conducting cam being sulficiently great to preventthe resilient member engaging both the stationary contact and thenon-conducting cam at the same time.

5. In a device of the character described, in combination, an insulatingbase, a com mutator having two cams, each substantially 180 degrees inlength, rotatably mounted on said base, one of said cams being ofnon-conducting material, and the other oi? conducting material, aresilient conducting member arranged to engage said cams, means torotate said commutator to compress said resilient means through theaction of the non-conducting cam, a stationary contact member, biasingmeans acting on said resilient means to disengage it from saidstationary contact member, said resilient means being electricallyconnected with said contact member when thus compressed, the end of saidnon-conducting cam terminating in a drop to permit said resilient meansto expand sufficiently to make contact with said conducting cam withoutleaving said stationary contact, whereby electrical continuity isestablished from said conduct-ing cam through said resilient lmeans tosaid stationary contact member.

said contact member, a commutator rotat-- ably mounted in said base andhaving two cams, each substantially 180 degrees kin length, one of saidcams having a face of non-conducting material, the other cam having aface of conducting material, and means for rotating said comniutator,whereby said resilient bridging member is moved into engagement withsaid contact member by engagement with said iace of non-conductingmaterial, said commutator having a drop at the end of said face oi`inon-conducting material, to permit the bridging member to expandslightly and establish electrical continuity between said Contact memberand said conducting cam face, said commutator having an abrupt drop atthe end of said conducting 'lia-ce to permit said bridging member tosnap oil the conducting face of said commutator, said bridging memberbeing provided with biasing means acting to disengage it from saidcontact member whereby contact will first be broken between saidconducting face and said bridging member and immediately thereafterbetween said bridging member and said contact member,

7. A switch mechanism comprising a rotatable commutator having aconducting cam terminating in a relatively large drop, and anon-conducting cam terminating in a smaller dropa first contact member,and a second contact member, said irst contact member comprising atwo-armed spring, one arm of which is engageable yand disengageable withrespect to said cams, and the other arm of which is engageable anddisengageable'with respect to said second contact, the larger droppermitting said springv contact to disengage said second contact, thesmaller drop not being suiiicient to permit said spring contact todisengage said second contact.

In witness whereof, I have hereunto subscribed my name.

REUBEN B. BENJAMIN.

